1. Field of the Invention
The present invention relates to a bracket and, more particularly, to a molding bracket for covering the end of a panel or the end-to-end seam between two panels subject to thermal expansion.
2. Description of the Prior Art
Brackets are placed over the end of a panel attached to a wall or ceiling to provide a decorative cover for the end of the panel or the end-to-end seam between two such panels. However, molding brackets for this purpose typically have not allowed for thermal expansion of the panel or panels. Accordingly, the panel can be restrained by the bracket as the panel expands, and the panel can buckle.
As illustrated in FIG. 1, a typical prior art molding bracket accepts an end of a panel 1 into a channel 2 provided by the molding bracket. Another channel 3, opposed to the channel 2, accepts an end of a second panel 4. However, unless sufficient space is left between the division bar 5 of the molding bracket and the facing ends of the panels 1 and 4, the panels will be restrained and will tend to buckle, as shown in dotted lines in FIG. 1, as they undergo thermal expansion.
Theoretically, this problem can be overcome by inserting the panels into the channels 2 and 3 only far enough so that the ends of the panels are covered, while leaving enough space between the division bar 5 and the ends of the panels to allow for thermal expansion. This solution is impractical for several reasons.
First, it requires an installer very carefully to measure the panels and secure them to the wall 6 at precisely determined locations that will provide a gap between the ends of the panel in their mounted positions. This is a very time-consuming, and thus costly, procedure. Even then, for relatively large panels the slightest error in mounting can result in a gap between the panels that is too large and thus the panels ends can be exposed if the panels undergo thermal contraction.
Second, if the panels are secured to the wall using a fastener such as that disclosed in co-pending U.S. patent application Ser. No. 07/304,485, assigned to the assignee of the present invention, this solution is even more impracticable. That fastener has a neck portion with a cross-section smaller than the cross-section of a hole in the panel through which the fastener passes, thus allowing for thermal expansion or contraction of the panel. Thus, the precise location of the panel in its mounted position is not positively determined when this fastener is used. Accordingly, it becomes even more difficult for an installer to properly locate the panels 1 and 4 relative to each other and to the division bar 5 to account for the movement of the ends of the panels as the panels expand and contract with temperature changes.
The prior art has attempted to address this problem with brackets such as those shown in U.S. Pat. Nos. 1,774,121, 3,445,972 and 4,485,600. However, all of these patents use resilient or deformable members attached to the division bar of a bracket such as that shown in FIG. 1. For example, U.S. Pat. No. 3,445,972 uses a deformable, depending tongue that extends from the division bar partway across each channel of the bracket. The tongue is meant to intercept a panel inserted into the channel to automatically limit the depth to which the panel extends into the channel. Then, if the panel expands after mounting, the tongue is meant to deform or break to allow such expansion and prevent buckling of the panel.
These brackets, however, also represent an incomplete solution to the problem since all of them rely on structure that actually bears against the end surface of the panel. Accordingly, they are not as useful for thin panels, such as fiberglass reinforced panels that are typically only about 1/16" thick. Such a panel inserted into the channel of a molding bracket like those discussed above may completely miss the structure intended to intercept it, and thus defeat the purpose of having such structure.